Tempskya is anextinctgenus oftree fern that lived during theCretaceous period. Fossils have been found across both the Northern and Southern hemispheres.[2] The growth habit ofTempskya was unlike that of any living fern or any other living plant, consisting of multiple conjoineddichotomous branching stems enmeshed within roots that formed a "falsetrunk".[3]
Thetrunk ofTempskya was actually a large collection ofstems surrounded byadventitious roots.[4] The false trunks can reach up to 6 metres (20 ft) in height and up to 50 centimetres (20 in) in diameter.[5] Small leaves grew from various points across the height of the trunk. This is in contrast to mosttree ferns, where typically large leaves grow from the top of the trunk.[5] Thinleaves have been discovered for the first time onTempskya wyomingense specimens;[1] the more commonly seenfossilizedleaf bases show that they covered the upper part of the trunk.[4]
Examination of cross sections of variousTempskya specimens shows that those with the largest trunks have the smallest number of stems, and vice versa.[6] From this, a possible growth pattern ofTempskya has been suggested: at thesporeling stage,Tempskya would consist of a single stem, which would begin to branch off distally. A "mantle" of adventitious roots would then develop around the stems to support them. Later on, many of the stems would begin todecay, while the adventitious roots would still provide support and absorb water for the grown plant.[6] This growth pattern has also been hypothesized forPsaronius.[6]
The first fossils ofTempskya was originally described in 1824 as theEndogenites erosa by Stokes and Webb, who considered it to be apalm tree. The genusTempskya was named byAugust Carl Joseph Corda in 1845, from specimens found in what is now the Czech Republic.[1] The fourspecies originally described by Corda were, in order:Tempskya pulchra,Tempskya macrocaula,Tempskya microrrhiza, andTempskya schimperi.[7]
Tempskya is the sole member of the family Tempskyaceae.[4] The family has been placed in the order "Filicales",[6] which is now split into a number of orders ofleptosporangiate ferns. They have been suggested to members ofCyatheales, based on morphological similarities of thepetiole and spores to some members of that order.[3]
Most taxonomists divideTempskya species into two groups, those with a simple cortex with only aparenchymatous inner cortex withoutsclerenchyma, while other species have an inner cortex with either discontinuous or continuous layers of sclerenchyma.[5]
Tempskya finds were thought to be exclusive to the Northern Hemisphere until specimens were discovered in Argentina and Australia, in 2003 and 2005, respectively.Tempskya fossils have also been discovered in theCzech Republic ,2002 andJapan ,1986.[2]
^abcdTaylor, Thomas N.; Taylor, Edith L.; Krings, Michael (2009)."Ferns and Early Fernlike Plants".Paleobotany : the biology and evolution of fossil plants (2nd ed.). Amsterdam: Academic Press. pp. 457–459.ISBN978-0-12-373972-8. Retrieved24 January 2012.
^Stephenson, Lloyd William (1936)."American Cretaceous Ferns of the Genus Tempskya".New Upper Cretaceous Ostreidae From the Gulf Region. Washington: United States Government Printing Office. p. 108. Retrieved25 January 2012.
